Whole grain cereals: functional components and health benefits

Cereal-based food products have been the basis of the human diet since ancient times. Dietary guidelines all over the world are recommending the inclusion of whole grains because of the increasing evidence that whole grains and whole-grain-based products have the ability to enhance health beyond the simple provision of energy and nutrients. In this review we will examine the main chemical components present in whole grains that may have health enhancing properties (dietary fiber, inulin, beta-glucan, resistant starch, carotenoids, phenolics, tocotrienols, and tocopherols) and the role that whole grains may play in disease prevention (cardiovascular diseases and strokes, hypertension, metabolic syndrome, type 2 diabetes mellitus, obesity, as well as different forms of cancer). The knowledge derived from the functional properties of the different chemical components present in whole grains will aid in the formulation and development of new food products with health enhancing characteristics.     

Prebiotics as functional foods: A review

Prebiotics are short chain carbohydrates that are non-digestible by digestive enzymes in humans and selectively enhance the activity of some groups of beneficial bacteria. In the intestine, prebiotics are fermented by beneficial bacteria to produce short chain fatty acids. Prebiotics also render many other health benefits in the large intestine such as reduction of cancer risk and increase calcium and magnesium absorption. Prebiotics are found in several vegetables and fruits and are considered functional food components which present significant technological advantages. Their addition improves sensory characteristics such as taste and texture, and enhances the stability of foams, emulsions and mouthfeel in a large range of food applications like dairy products and bread. This contribution reviews bioactives from food sources with prebiotic properties. Additionally, food application of bioactive prebiotics, stimulation of the viability of probiotics, health benefits, epidemiological studies, and safety concerns of prebiotics are also reviewed.     

纳米技术在功能性食品中应用

近年来,纳米技术在功能性食品中应用正处快速发展阶段,其作为高新技术在功能性食品领域应用研究得到越来越多关注;纳米技术不仅可用于功能性食品生产和加工,也可提高生物活性、吸收率、稳定性、降低毒性。该文重点介绍纳米技术在功能性食品中应用。     

Effect of food processing on the resistant starch content of cereals and cereal products – a review

Depending on the conditions, processing of cereal grains may cause an increase or a decrease in the resistant starch (RS) content. This review discusses the impact of some of the processing techniques (cooking, tempering and extrusion) on the RS contents of cereals and cereal products. In addition to processing, the review briefly summarises the effects of lipids, dietary fibre and sugars, which may be present within the food matrix, on starch digestibility. The review also provides definitions for the four types of RS (RS type 1, 2, 3 and 4) and brief information about the beneficial effects of RS on human health.     

Starch and non-starch polysaccharides in some cereal foods

The polysaccharide content of some cereal foods is reported, measured by a recently described technique. This method allows accurate determination of plant cell wall and other plant polysaccharides and identification and measurement of starch made resistant to digestion by α-amylase and pullulanase during food processing (resistant starch). The results reported are at variance with values for dietary fibre measured by other published methods by a factor of up to 10 in some foods. This is due partly to the failure of some methods to identify resistant starch separately from NSP and partly to other details of methodology. Implied in these findings is the need to critically assess methods used for the chemical determination of non-starch polysaccharides and the need to be cautious in interpreting dietary-fibre-intake data especially in population studies.     

谷物食品研究现状及发展趋势

作为人类最基本的膳食组成,谷物食品无论在食品市场还是科研领域都占有重要的地位。近年来,市场上出现了越来越多的全谷物食品。以面包、面条、饼干以及谷物棒4种谷物产品为例,综述了近年来谷物食品的研究现状,并分析展望了全谷物食品的市场前景与发展趋势。     

Determination of fumigants in cereals and cereal products by capillary gas chromatography

This study describes two methods for the quantitative determination of the residual fumigants ethylene dichloride (EDC), carbon tetrachloride (CCl4), trichloroethylene (TCE), ethylene dibromide (EDB) and tetrachloroethylene (PCE) in cereals (especially wheat) and other foodstuffs. In the first method, a micro steam distillation- solvent extraction apparatus is used, while the second method is based on a headspace technique. For the quantitative determination of carbon tetrachloride in cereals, the multiple headspace technique is not retained because it is too time-consuming. The analysis of the different fumigants is performed by electron-capture gas chromatography, using a fused silica capillary column, CP sil 8 CB. With the steam distillation-solvent extraction method, recoveries from 95.9% to 100.5% are obtained for the fumigants, added at two different levels. The standard deviation varies between 1.1% and 6%. Using the simple headspace technique, recoveries from 73.5% to 85.1% with a standard deviation of between 1.7% and 6.6% have been reached for the fumigants in cereals fortified at two different levels. The absolute detection limits for the five fumigants EDC, CCl4, TCE, EDB and PCE, in both methods, are 30, 0.25, 1.1, and 0.5 pg, respectively.     

Determination of fumigants in cereals and cereal products by capillary gas chromatography

Summary This study describes two methods for the quantitative determination of the residual fumigants ethylene dichloride (EDC), carbon tetrachloride (CCl₄), trichlorethylene (TCE), ethylene dibromide (EDB) and tetrachlorethylene (PCE) in cereals (especially wheat) and other foodstuffs. In the first method, a micro steam distillation- solvent extraction apparatus is used, while the second method is based on a headspace technique. For the quantitative determination of carbon tetrachloride in cereals, the multiple headspace technique is not retained because it is too time-consuming. The analysis of the different fumigants is performed by electron-capture gas chromatography, using a fused silica capillary column, CP sil 8 CB. With the steam distillation-solvent extraction method, recoveries from 95.9% to 100.5% are obtained for the fumigants, added at two different levels. The standard deviation varies between 1.1 % and 6%. Using the simple headspace technique, recoveries from 73.5% to 85.1 % with a standard deviation of between 1.7% and 6.6% have been reached for the fumigants in cereals fortified at two different levels. The absulute detection limits for the five fumigants EDC, CCl₄, TCE, EDB and PCE, in both methods, are 30, 0.25, 1.1, and 0.5 pg, respectively.

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Bestimmung von Begasungsmitteln in Getreide und Getreideprodukten durch Capillar-Gaschromatographie

Zusammenfassung Es wurden zwei Methoden für die quantitative Bestimmung der Restmengen von Begasungsmitteln wie 1,2-Dichlorethan (EDC), Tetrachlorkohlenstoff (CCl₄), Trichlorethylen (TCE), 1,2-Dibromethan (EDB) und Tetrachlorethylen (PCE) im Getreide, insbesondere Weizen, und in Lebensmitteln beschrieben. Das erste Verfahren basiert auf einer Mikrodampfdestillation-Lösungsmittelextraktion, während für das zweite die Kopfraumtechnik verwendet wurde. Da mehrfache Kopfraum-Extraktion bei der Bestimmung des Tetrachlorkohlenstoffes in Getreide zu zeitraubend ist, wurde diese Methode nicht beibehalten. Die Begasungsmittel wurden durch Elektroneneinfang-Gaschromatographie unter Verwendung einer CP sil. 8 CB silica Glaskolonne bestimmt. Mit der Dampfdestillation-Lösungsmittelextraktion wird eine Ausbeute von 95,9 bis 100,5% für fünf Begasungsrestmengen in zwei verschiedene Konzentrationen erreicht. Die Standardabweichung varriiert zwischen 1,1 und 6%. Die einfache Kopfraum-Extraktion gibt für zwei verschiedene Konzentrationen eine Ausbeute von 73,5 bis 85,1% mit einer Standardabweichung von 1,7 bis 6,6%. Die absolute Nachweisgrenze beider Methoden für die fünf Begasungsmittel EDC, CCl₄, TCE, EDB und PCE ist 30, respektive 0,25, 1,1 und 0,5 pg.

     

降糖类保健食品配方及功效成分研究现状与展望

为了解降糖类保健食品功效及配方现状,通过对国家食品药品监督管理局批准上市的314种降糖类保健食品配方及功效成分进行分类和整理,对其原料使用频次、活性成分和保健功能等情况进行了全面分析。着重介绍了使用频率较高的活性成分黄酮类,有机铬类和皂苷类等在控制血糖、调控糖代谢和保护胰岛细胞等缓解糖尿病症状方面的作用及其机制。旨在总结辅助降糖类保健食品的配方规律,为今后降血糖保健食品的开发提供参考。     

Mycotoxins and the cereals industry—a review

Mycotoxicoses in humans and animals associated with the consumption of mouldy cereals have long been recognized and many are now linked with the occurrence of specific mould metabolites (mycotoxins). Mycotoxins which have been detected in cereals are aflatoxins, zearalenone, ochratoxin A, nivalenol, deoxynivalenol, T-2 toxin and diacetoxyscirpenol and of these only aflatoxin B₁ has so far been shown to exhibit serious toxicity to humans. Surveys have shown that the occurrence of mycotoxins in cereals in the UK and USA is rare except for localized problems with corn in the Southern United States. Also it is clear that aflatoxins are more likely to occur in warm humid climates while the other mycotoxins listed above are more characteristic of temperate climates if there is a wet harvest.     

Sensitive method for the rapid determination of phytate in cereals and cereal products

A rapid method is described for the colorimetric determination of 1.5–15 μg phytate phosphorus in concentrations as low as 3 μg ml^?1 in extracts of cereal grains and cereal products. The phytic acid is precipitated with an acidic iron-III-solution of known iron content. The decrease of iron in the supernatant is a measure for the phyticacid content.     

保健食品开发中的新技术应用

在保健食品加工制造过程中最大限度地保留功效成分的活性,并对其调节机体功能进行科学评价是研制开发保健食品的关键。 传统的食品加工工艺往往难以满足研制开发保键食品的技术要求,因此迫切需要采用现代科技。现将保健食品研制开发中所需高新技术简介如下:     

Iron bioavailability in iron-fortified cereal foods: The contribution of in vitro studies

Iron deficiency anemia is the most common nutritional deficiency in humans. Not all dietary ingested iron, heme or nonheme, will be available to absorption and negative imbalance between iron requirements and absorption leads to iron deficiency and/or anemia. The recommended iron values usually are based on the genetic and on diet iron-bioavailability, which can be considered as the principal factor that change among the cultures and influences the distinct levels of recommendation among countries. Dietary changes present practical limitations due to be difficult to change food habits. The iron food fortification is considered more cost effective and economically more attractive than iron supplementation. There are many iron compounds available to be used in iron fortification. Cereals represent a target food group to iron fortification programs due to high consumption and the in vitro studies can be useful to estimate the relative iron bioavailability in large number of products in short time and with a low cost. Wheat flour baked into bread or not was the main product tested in in vitro bioavailability studies and ferrous sulfate was the principal iron compound used in the fortification studies. However, iron bioavailability from ferrous sulfate is lower than from other compounds, such FeNaEDTA or ferric pyrophosphate. The variables level of fortification, storage, level of extraction, baking and also the association or not with other chemical compound seems to influence the results obtained.     

Fate of mycotoxins in cereals during extrusion cooking: a review.

Extrusion cooking is one of the fastest growing food-processing operations in recent years due to several advantages over traditional methods. Apart from its main goal of improving the quality of intermediate and final processed products, it may incidentally also improve safety because of the potential to reduce mycotoxin levels in cereals. This review is focused on extrusion cooking and aims to give a general overview of its impact in reducing mycotoxin levels in cereals. Extrusion cooking generally decreases the mycotoxins levels at rates depending on different factors such as the type of extruder, the type of screw, the die configuration, the initial mycotoxin concentration, the barrel temperature, the screw speed, the moisture content of the raw material and the use of additives. Reductions of 100, 95 and 83% for fumonisins, aflatoxins and zearalenone, respectively, have been reported during extrusion cooking of cereals, while lower reductions were observed for deoxynivalenol, ochratoxin A and moniliformin, where maximum reductions did not exceed 55, 40 and 30%, respectively.     

Bound phytophenols from ready-to-eat cereals: Comparison with other plant-based foods

Whole-grain diets are linked to reduced risk of several chronic diseases (heart disease, cancer, diabetes, metabolic syndrome) and all-cause mortality. There is increasing evidence that these benefits are associated with the gut microbiota and that release of fibre-related phenolic metabolites in the gut is a contributing factor. Additional sources of these metabolites include fruits and vegetables, but the evidence for their protective effects is less well established. With respect to the availability of bound phytophenols, ready-to-eat cereals are compared with soft fruits (considered rich in antioxidants) and other commonly consumed fruits and vegetables. The results demonstrated that when compared with an equivalent serving of fruits or vegetables, a recommended portion of whole-grain cereals deliver substantially higher amounts of bound phytophenols, which are available for metabolism in the colon. The increased amount of these phenolic metabolites may, in part, explain the evidence for the protective effects of whole-grain cereals.     

The development of fruit‐based functional foods targeting the health and wellness market: a review

Functional foods and their health benefits beyond individual nutrients present challenges to the traditional ‘nutrition’ approach to foods. Epidemiological studies suggest that regular or increased consumption of fruits may promote general health and well‐being as well as reduce the risk of chronic diseases. Therefore, a broad range of research amongst academic, industry and government institutes has been stimulated in attempts to add the goodness of fruits into popular consumer foods. This article provides a brief overview of the research opportunities in the emerging functional foods area, with an emphasis on fruit‐derived products. Based on recent research in the fruit‐based functional food area, a structured approach for designing and developing functional finished products is presented. Included are the technical challenges and their associated solutions during food design, formulation, processing and storage. A consumer‐oriented food product development process is highlighted. Controlling the interactions among the targeted bioactives and other food components during food processing, handling and storage is the key to ensure that a stable and appealing functional food is produced. Manipulating the beneficial synergies among food ingredients, and among food formulation and processing methods, has the potential to lead to substantial food innovations.